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  * @Id: curs_clear.3x,v 1.11 2007/12/29 15:58:38 tom Exp @
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<H1>curs_clear 3x</H1>
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<PRE>
<!-- Manpage converted by man2html 3.0.1 -->
<STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>                                           <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>


</PRE>
<H2>NAME</H2><PRE>
       <STRONG>erase</STRONG>, <STRONG>werase</STRONG>, <STRONG>clear</STRONG>, <STRONG>wclear</STRONG>, <STRONG>clrtobot</STRONG>, <STRONG>wclrtobot</STRONG>,
       <STRONG>clrtoeol</STRONG>, <STRONG>wclrtoeol</STRONG> - clear all or part of a <STRONG>curses</STRONG> window


</PRE>
<H2>SYNOPSIS</H2><PRE>
       <STRONG>#</STRONG> <STRONG>include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>

       <STRONG>int</STRONG> <STRONG>erase(void);</STRONG>
       <STRONG>int</STRONG> <STRONG>werase(WINDOW</STRONG> <STRONG>*win);</STRONG>
       <STRONG>int</STRONG> <STRONG>clear(void);</STRONG>
       <STRONG>int</STRONG> <STRONG>wclear(WINDOW</STRONG> <STRONG>*win);</STRONG>
       <STRONG>int</STRONG> <STRONG>clrtobot(void);</STRONG>
       <STRONG>int</STRONG> <STRONG>wclrtobot(WINDOW</STRONG> <STRONG>*win);</STRONG>
       <STRONG>int</STRONG> <STRONG>clrtoeol(void);</STRONG>
       <STRONG>int</STRONG> <STRONG>wclrtoeol(WINDOW</STRONG> <STRONG>*win);</STRONG>


</PRE>
<H2>DESCRIPTION</H2><PRE>
       The  <STRONG>erase</STRONG>  and <STRONG>werase</STRONG> routines copy blanks to every posi-
       tion in the window, clearing the screen.

       The <STRONG>clear</STRONG> and <STRONG>wclear</STRONG> routines are like <STRONG>erase</STRONG>  and  <STRONG>werase</STRONG>,
       but  they also call <STRONG>clearok</STRONG>, so that the screen is cleared
       completely on the next call to <STRONG>wrefresh</STRONG>  for  that  window
       and repainted from scratch.

       The  <STRONG>clrtobot</STRONG> and <STRONG>wclrtobot</STRONG> routines erase from the cursor
       to the end of screen.  That is, they erase all lines below
       the  cursor  in the window.  Also, the current line to the
       right of the cursor, inclusive, is erased.

       The <STRONG>clrtoeol</STRONG> and <STRONG>wclrtoeol</STRONG> routines erase the current line
       to  the  right of the cursor, inclusive, to the end of the
       current line.

       Blanks created by erasure have the current background ren-
       dition (as set by <STRONG>wbkgdset</STRONG>) merged into them.


</PRE>
<H2>RETURN VALUE</H2><PRE>
       All  routines  return the integer <STRONG>OK</STRONG> on success and <STRONG>ERR</STRONG> on
       failure.  The SVr4.0 manual says "or a non-negative  inte-
       ger if <STRONG>immedok</STRONG> is set", but this appears to be an error.

       X/Open  defines  no error conditions.  In this implementa-
       tion, functions using a window pointer parameter return an
       error if it is null.


</PRE>
<H2>NOTES</H2><PRE>
       Note that <STRONG>erase</STRONG>, <STRONG>werase</STRONG>, <STRONG>clear</STRONG>, <STRONG>wclear</STRONG>, <STRONG>clrtobot</STRONG>, and <STRONG>clr-</STRONG>
       <STRONG>toeol</STRONG> may be macros.


</PRE>
<H2>PORTABILITY</H2><PRE>
       These functions are described in the XSI Curses  standard,
       Issue  4.   The standard specifies that they return <STRONG>ERR</STRONG> on
       failure, but specifies no error conditions.

       Some historic curses implementations had,  as  an  undocu-
       mented  feature,  the  ability  to  do  the  equivalent of
       <STRONG>clearok(...,</STRONG> <STRONG>1)</STRONG> by saying <STRONG>touchwin(stdscr)</STRONG>  or  <STRONG>clear(std-</STRONG>
       <STRONG>scr)</STRONG>.  This will not work under ncurses.

       This  implementation, and others such as Solaris, sets the
       current position to 0,0 after  erasing  via  <STRONG>werase()</STRONG>  and
       <STRONG>wclear()</STRONG>.   That fact is not documented in other implemen-
       tations, and may not be true of implementations which were
       not derived from SVr4 source.

       Not  obvious  from  the  description, most implementations
       clear the screen after <STRONG>wclear</STRONG> even for a subwindow or  de-
       rived window.  If you do not want to clear the screen dur-
       ing the next <STRONG>wrefresh</STRONG>, use <STRONG>werase</STRONG> instead.


</PRE>
<H2>SEE ALSO</H2><PRE>
       <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_outopts.3x.html">curs_outopts(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>


                                                         <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>
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